Electrostatic discharge (ESD) causes circuit failures. ESD may be caused by current surges or arcing due to lightning, human contact (i.e., charged non-conductive element contacting a conductive element), or “hot” connect or disconnect of circuits via cable connectors, Typically, ESD reaches a circuit via pins at the cable level, circuit board level, or chip level. ESD pulses cause power, high voltage, or current spikes (i.e., power surges) that can damage electronics that are not equipped to dissipate the power or withstand peak voltages or currents.
Some classes of ESD protection circuits include semi-conductor layering schemes (U.S. Pat. No. 6,091,082), voltage clamps (U.S. Pat. Nos. 6,259,573 and 5,903,415), and resistive bleed circuits (U.S. Pat. No. 5,539,598).